5.15-stable patches

added patches:
	ptrace-slightly-saner-get_dumpable-logic.patch

diff --git a/queue-5.15/ptrace-slightly-saner-get_dumpable-logic.patch b/queue-5.15/ptrace-slightly-saner-get_dumpable-logic.patch
new file mode 100644 (file)
index 0000000..815872a
--- /dev/null
+++ b/queue-5.15/ptrace-slightly-saner-get_dumpable-logic.patch
@@ -0,0 +1,109 @@
+From 31e62c2ebbfdc3fe3dbdf5e02c92a9dc67087a3a Mon Sep 17 00:00:00 2001
+From: Linus Torvalds <torvalds@linux-foundation.org>
+Date: Wed, 13 May 2026 11:37:18 -0700
+Subject: ptrace: slightly saner 'get_dumpable()' logic
+
+From: Linus Torvalds <torvalds@linux-foundation.org>
+
+commit 31e62c2ebbfdc3fe3dbdf5e02c92a9dc67087a3a upstream.
+
+The 'dumpability' of a task is fundamentally about the memory image of
+the task - the concept comes from whether it can core dump or not - and
+makes no sense when you don't have an associated mm.
+
+And almost all users do in fact use it only for the case where the task
+has a mm pointer.
+
+But we have one odd special case: ptrace_may_access() uses 'dumpable' to
+check various other things entirely independently of the MM (typically
+explicitly using flags like PTRACE_MODE_READ_FSCREDS).  Including for
+threads that no longer have a VM (and maybe never did, like most kernel
+threads).
+
+It's not what this flag was designed for, but it is what it is.
+
+The ptrace code does check that the uid/gid matches, so you do have to
+be uid-0 to see kernel thread details, but this means that the
+traditional "drop capabilities" model doesn't make any difference for
+this all.
+
+Make it all make a *bit* more sense by saying that if you don't have a
+MM pointer, we'll use a cached "last dumpability" flag if the thread
+ever had a MM (it will be zero for kernel threads since it is never
+set), and require a proper CAP_SYS_PTRACE capability to override.
+
+Reported-by: Qualys Security Advisory <qsa@qualys.com>
+Cc: Oleg Nesterov <oleg@redhat.com>
+Cc: Kees Cook <kees@kernel.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/linux/sched.h |    3 +++
+ kernel/exit.c         |    1 +
+ kernel/ptrace.c       |   22 ++++++++++++++++------
+ 3 files changed, 20 insertions(+), 6 deletions(-)
+
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -896,6 +896,9 @@ struct task_struct {
+        */
+       unsigned                        sched_remote_wakeup:1;
+ 
++      /* Save user-dumpable when mm goes away */
++      unsigned                        user_dumpable:1;
++
+       /* Bit to tell LSMs we're in execve(): */
+       unsigned                        in_execve:1;
+       unsigned                        in_iowait:1;
+--- a/kernel/exit.c
++++ b/kernel/exit.c
+@@ -540,6 +540,7 @@ static void exit_mm(void)
+        */
+       smp_mb__after_spinlock();
+       local_irq_disable();
++      current->user_dumpable = (get_dumpable(mm) == SUID_DUMP_USER);
+       current->mm = NULL;
+       membarrier_update_current_mm(NULL);
+       enter_lazy_tlb(mm, current);
+--- a/kernel/ptrace.c
++++ b/kernel/ptrace.c
+@@ -288,11 +288,24 @@ static bool ptrace_has_cap(struct user_n
+       return ns_capable(ns, CAP_SYS_PTRACE);
+ }
+ 
++static bool task_still_dumpable(struct task_struct *task, unsigned int mode)
++{
++      struct mm_struct *mm = task->mm;
++      if (mm) {
++              if (get_dumpable(mm) == SUID_DUMP_USER)
++                      return true;
++              return ptrace_has_cap(mm->user_ns, mode);
++      }
++
++      if (task->user_dumpable)
++              return true;
++      return ptrace_has_cap(&init_user_ns, mode);
++}
++
+ /* Returns 0 on success, -errno on denial. */
+ static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
+ {
+       const struct cred *cred = current_cred(), *tcred;
+-      struct mm_struct *mm;
+       kuid_t caller_uid;
+       kgid_t caller_gid;
+ 
+@@ -353,11 +366,8 @@ ok:
+        * Pairs with a write barrier in commit_creds().
+        */
+       smp_rmb();
+-      mm = task->mm;
+-      if (mm &&
+-          ((get_dumpable(mm) != SUID_DUMP_USER) &&
+-           !ptrace_has_cap(mm->user_ns, mode)))
+-          return -EPERM;
++      if (!task_still_dumpable(task, mode))
++              return -EPERM;
+ 
+       return security_ptrace_access_check(task, mode);
+ }

diff --git a/queue-5.15/series b/queue-5.15/series
index aee5c94a96222a23ba34fbcf5b9219c4d4b3e021..381d32fd7c968ca8e99ecab86f36da4272f2b93e 100644 (file)
--- a/queue-5.15/series
+++ b/queue-5.15/series
@@ -357,3 +357,4 @@ mptcp-use-mptcp_rst_emptcp-for-ack-hmac-validation-failure.patch
 mptcp-sockopt-set-timestamp-flags-on-subflow-socket-not-msk.patch
 mptcp-fix-scheduling-with-atomic-in-timestamp-sockopt.patch
 x86-cpu-amd-prevent-improper-isolation-of-shared-resources-in-zen2-s-op-cache.patch
+ptrace-slightly-saner-get_dumpable-logic.patch